1. Field of the Invention
The present invention relates to an agricultural machine for the harvesting of fodder comprising a frame to which is connected a structure situated, at least partially, above at least one pick-up device for picking up plants lying on the ground, the pick-up device comprising teeth with teeth points describing a curve envelope when the teeth are driven, the machine also comprising at least one processing device for processing the picked up plants which is situated close to the pick-up device, and a guiding device for guiding the plants which is situated at least partially above and at a small distance from the pick-up device, the guiding device being displaceable with respect to the pick-up device about a main instantaneous rotation center, by means of a displacement device comprising a first connecting means and a second connecting means of the guiding device to the structure, the first connecting means enabling the guiding device to pivot about a first instantaneous rotation center, the second connecting means enabling the guiding device to pivot about a second instantaneous rotation center, the displacement device being able to be placed in at least a first position and a second position, the guiding device comprising a front part having a lower front end, a rear part delimited by a rear end, and an intermediate part connecting the front part to the rear part.
2. Discussion of the Background
On a known machine of this type, the pick-up device comprises a rotor with teeth of the “pick-up” type. The rotor is partially surrounded by a guiding surface formed for example by a set of curved blades, between which the teeth carried by the rotor rotate, and with respect to which curved blades the teeth points emerge. When the rotor rotates, the teeth pick up the plants at the level of the ground, lift them and project them towards the rear along the guiding surface. In the first position provided on this machine, the lower front end of the guiding device is raised greatly above the ground to allow the passage of a large-volume windrow towards the pick-up device. In this first position, the intermediate part of the guiding device extends substantially to the horizontal above the pick-up device and substantially at the same height as the lower front end, hence the intermediate part is situated at a great distance from the teeth points of the pick-up device. The result of this is that in this first position, the intermediate part of the guiding device cannot properly keep the plants in contact with the teeth which are situated at the front and on the top of the pick-up device. Consequently, the plants are carried along in an irregular manner towards the processing device located downstream. In addition, a harmful accumulation of plants can occur between the pick-up device and the processing device, or within the latter. The known machine also comprises a second position provided in particular for the picking up of windrows which are light or small in volume. In this position, the lower front end of the guiding device is brought closer to the ground than in the first position. It nevertheless remains at too great a height from the ground to prevent the projections of plants towards the front when the toothed rotor rotates, these projections existing due to the lightness of the picked up plants. These projections fall down in a random manner on the windrow which has not yet been picked up, situated at the front of the machine, and make it irregular. Consequently, the supplying with plants of the pick-up device and of the processing device downstream is irregular, for example in the form of bundles of variable volume. This drawback also exists when the machine is picking up plants which are spread out on the ground in short strands. In the second position of the known machine, the intermediate part and the rear part are very close to the pick-up device to the extent that they are situated lower than the teeth points and nearly touch the guiding surface. Consequently, the flow of light plants is braked when it passes between the pick-up device and the intermediate and rear parts, which reduces the output per hour of the machine.